1. Field
The field generally relates to data storage devices and systems.
2. Background
A data storage device or system, such as a network server, file server, or Internet server may be used to store data for access by other entities, such as client devices. Such a data storage systems may include a number of mass storage devices, such as disk drives, where reading data from the drives and writing data to the drives is controlled by an operating system of the data storage system and/or a controller external to the data storage system. Often the disk drives are in a data storage system that is not physically inside, but is external to the network server or file server.
For example, a data storage system, may be a storage server having a special-purpose or general purpose operating system configured to provide storage services, such as to store and retrieve data on behalf of one or more client processing systems (clients). A storage server can be used for many different purposes, such as to provide multiple users with access to shared data or to backup mission critical data.
A file server is an example of a storage server. A file server operates on behalf of one or more clients to store and manage shared files in a set of mass storage devices, such as magnetic or optical storage based disks or tapes. The mass storage devices may be organized into one or more volumes of Redundant Array of Inexpensive Disks (RAID) and/or RAID groups.
The mass storage devices may be obtained from or provided by a number of manufacturers or vendors. Moreover, such mass storage devices may come from various batches of production, such as production batches of devices assembled from batches of components having similar characteristics and/or defects. As a result, a data storage system or server that includes mass storage devices from a single manufacturer or batch may suffer if these mass storage devices have the same probable time to failure. Specifically, if the data storage system or server is exposed to a setting or condition that exposes or exacerbates the most probable failure, plural mass storage devices may fail or experience functional errors simultaneously or within an undesirably short period of time. Thus, the data storage system may fail, become unusable, or become inoperable for an undesirably long period of time, or data may be lost or unrecoverable through normal RAID operations.